Since resources and vehicle timers are only bound to yourself, the only thing you have to fear is the laughter of your teammates. Spawning a vehicle does not prevent anyone else from spawning a vehicle so don't hesitate to spawn them as often as you want to get some practice. Just try not to ram into friendly vehicles, especially ramming into friendly Liberators or Galaxys can cause a huge amount of havoc and can make people rage at you, so try to practice a few meters away from the actual warpgate traffic.
Since GU04 you can access the VR training where you can spawn vehicles without cooldown or resource cost. To access it, just go to the warpgate and use the continent transfer terminal. At the bottom it has a button that brings you directly to the VR training.
You can also access all weapons and upgrades, including weapons you do not have unlocked, and try them out on target dummys in the landscape as well as in the shooting range where a mix of hostile and friendly targets pop up constantly.